In the majority of standard chronographs, such three functions are controlled through a column wheel. As shown on FIG. 1, such column wheel 1 is a rotatable element comprising triangular teeth 2 in its lower portion, and columns 3 in its upper portion. When one exerts pressure on the end 4 of the large lever 5, the latter pivots in the sense of arrow F and by its other end drives said column wheel in rotation thanks to the triangular teeth 2 of the latter. When such column wheel turns, it drives and displaces on one hand the end of the hammer 6 which releases heart piece 7 of the center wheel 8 and, on the other hand, the intermediate lever 9 which acts on the intermediate wheel 10 by bringing this latter into contact with the center wheel 8 in order to mesh with the latter. One thus obtains the starting of the chronograph. Upon a second pressure being exerted at 4, the beak of brake 11 which up to now remained in its initial position, being held by column 3a, swings between the two neighbouring columns 3a and 3b and its rounded portion 12 moves to block the center wheel 8. One thus obtains the stop function of the chronograph. Finally, a third pressure exerted on the large lever 5 brings about the reset to zero since the intermediate wheel 10 is released and hammer 6 is brought to bear on the heart piece 7 in order to bring wheel 8 back to zero.
It may be determined from FIG. 1 that the column wheel shown by way of example includes six columns and eighteen teeth. It is thus necessary to exert pressure on the large lever 5 three times in order that a column take the place of the preceding column, which corresponds to the three functions of the chronograph.
The utilization of a column wheel complicates the construction of the chronograph and requires that the ends of the hammers and levers assuring the control of the functions are concentrated at a single point. There are already known chronographs provided with arrangements aiming to suppress the column wheel and to simplify the construction.
To this end, Swiss patent CH-466 152 describes a chronograph comprising a first lever operated at one end by a start push-button and at the other end by a second stop push-button and a second lever operated by a third reset- to-zero push-button.
In the same manner, Swiss patent CH-579 794 describes a chronograph in which the column wheel is replaced by a cam at three levels effecting the three chronograph functions.
Nevertheless, these arrangements do not enable a more judicious distribution of the elements of the mechanism over the entire surface of the watch.
Consequently, the purpose of this invention is to overcome these difficulties.